After reading this article you will learn about the conservation of biological diversity by controlling various kinds of pollution.
1. Water Pollution Control:
The treatment process for industrial waste includes:
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(i) Removal of colloidal solids by flocculation with coagulants and electrolytes followed by sedimentation and filtration.
(ii) Removal of suspended solids by screening or settling.
(iii) Removal of oil and greasy solids by flotation and skimming aided by chemical treatment if necessary.
(iv) Re-oxygenation of wastes by aeration method.
(v) De-colorization by chemical treatment with sedimentation or filtration or combination of both.
(vi) Removal of excess acidity or alkalinity by adding chemical or mixing alkaline wastes with acidic wastes and vice-versa.
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(vii) Removal of stabilization of dissolved solids by chemical precipitation or biological processes or by combination of both.
(viii) The techniques given in treatment of effluents can successfully be utilized for removal of industrial pollution.
2. Soil Pollution:
(1) To avoid soil contamination due to pesticide pollution, the cropping of plants that accumulate pesticides has been suggested for decontaminating soils.
(2) Heavy irrigation for the removal of contaminants from soil is another alternative to remove toxic substances.
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(3) Adding absorbent material has been suggested as a means of making persistent chemicals less harmful.
(4) Activated carbon is most popular absorbent and can be specialised technique when large quantities of herbicide are required for non-recurrent control of a resistant weed.
(5) For biological control of pests by predators, sterile male release and use of pathogens for pest control are the new developed techniques.
(6) Salt polluted Solids due to water logging are called Saline Soils. Salts make the soil harder and infertile hence for regeneration the mixture of Gypsum and zinc sulphate is used to make the soil fertile. Non saline alkali lands are called user lands which can also be made fertile by post reclamation agronomy.
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(7) For removing solid waste, compost manure is used as soil conditioner or plant mulch. As semi-moist conditions of composting are favourable to fungi and actinomycetes, they form the predominating group of micro-organisms. Bacteria assists in upper range of moisture and species of Penicillium, Rhizopus, Aspergillus and Mucor are also available in compost.
(8) As cement dust settles on the soil blocking pores and leaving finest particles at surface to form crusts upon drying hence soil can be improved by treating with polymers to improve its physical structure by binding aggregates in long chain molecules.
Polymers have been shown to be effective in increasing hydraulic conductivity and porosity, improving water holding capacity, reducing erosion and weakening crust strength. The use of polyacrylamide as soil conditioner to stabilize aggregates has been well documented. Carbonic polymers have been tested and prompted for anticrusting properties.
3. Vehicle Emission Control Measures:
For four stroke SI engine, the following points are noted to control emissions:
(i) Exhaust emission Control:
It requires following steps:
(a) Fuel system design modification
(b) Engine operating variable modification
(c) Exhaust gas treatment devices
(d) Fuel modifications
(e) Exhaust gas circulation for NOx control.
(ii) Evaporative emission control. Here two basic techniques are used:
(i) Vapour recovery system
(ii) Adsorption regeneration system.
4. Radioactive Pollution Control:
In India there is urgent need for radioactive monitoring and control of air and waste water.
The main nuclear installations in India are as follows:
(i) Nuclear Power Reactors:
(a) Rajasthan atomic power plants
(b) Tarapore atomic power plants
(c) Kalpakkam atomic power plants
(ii) Industrial Establishments:
(a) Indian Rare Earths Ltd.
(b) Uranium Corporation of India
(c) Nuclear Fuels Complex
(iii) Research Establishments:
(a) Atomic Mineral Division
(b) Bhabha Atomic Research Centre
(c) Indira Gandhi Reactor Research Establishment
(d) Centre for advanced Technology
In fact all these establishments release radioactive pollutants in water as well as in atmospheric air.
Although in most of the establishments effects are made to collect radioactive waste in special plastic containers and effluent is discharged after making it free from radioactive pollution but experimental results have shown that industrial effluents do contain radioactive elements which should be prevented immediately and effluent should be discharged only after careful examination of the effluent material.